Adopting a dog is a huge decision and knowing signs to watch out for when choosing a dog can help you end up with the perfect pup. According to Business Insider, if a dog is excessively barking or growling at you this could be an indicator that a dog will have trouble adjusting to new people and situations. Conversely, if a dog seems too calm and has little to no reaction when meeting you this could be a sign of a more serious medical problem.